000 AXNT20 KNHC 120530 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST MON JAN 12 2009 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0445 UTC. ...THE ITCZ... ITCZ IS CENTERED ALONG 6N10W 3N21W 2N31W 1N42W AND INTO NE BRAZIL NEAR 1S48W. SCATTERED MODERATE CONVECTION IS S OF 5N BETWEEN 20W-34W. SCATTERED MODERATE CONVECTION IS ALSO S OF 6N BETWEEN 36W-41W. ...DISCUSSION... GULF OF MEXICO... SOUTHWESTERLY FLOW ALOFT CONTINUES TO INCREASE ACROSS THE GULF REGION AS A DEEP TROUGH OVER THE E CONUS MOVES EASTWARD. A SURFACE COLD FRONT ASSOCIATED WITH THIS DEEP TROUGH EXTENDS FROM THE N FLORIDA PENINSULA NEAR 30N82W TO 24N91W ACROSS THE BAY OF CAMPECHE TO S MEXICO NEAR 19N95W. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ALONG AND WITHIN 90 NM E OF THE COLD FRONT. THIS ACTIVITY IS BEING ENHANCED IN THE SW QUADRANT OF AN UPPER LEVEL JET MAXIMUM LOCATED OVER THE SE CONUS. THE COLD FRONT IS FORECAST TO BECOME STATIONARY AND THEN BECOME REINFORCED MONDAY NIGHT. THIS FRONT IS THEN FORECAST TO MOVE SOUTHWARD ACROSS THE REMAINDER OF THE GULF ON TUESDAY. INCREASED NORTHERLY WINDS...AS WELL AS COOLER AND DRIER CONDITIONS...ARE PRESENT IN THE WAKE OF THE COLD FRONT. ALSO...A GALE WARNING IS IN EFFECT FOR PORTIONS OF THE SW GULF. AHEAD OF THE FRONT...INCLUDING PORTIONS OF THE SE GULF...THE RETURN FLOW AROUND A 1028 MB SURFACE HIGH OVER THE CENTRAL ATLC NEAR 34N46W IS RESULTING IN E TO SE SURFACE WINDS OF 10 KT OR LESS. ADDITIONALLY...STRONG N TO NE SURFACE WINDS ARE FORECAST TO BLOW THROUGH THE ISTHMUS OF TEHUANTEPEC RESULTING IN GALE FORCE WINDS IN THE E PACIFIC REGION BEGINNING AT 12/0600 UTC. CARIBBEAN SEA... AN UPPER RIDGE IS PRESENT ACROSS THE CARIBBEAN SEA...WITH THE UPPER RIDGE AXIS EXTENDING FROM N VENEZUELA NEAR 11N70W TO 17N80W TO 21N85W. SUBSIDENCE AND STABLE ATMOSPHERIC CONDITIONS ASSOCIATED WITH THIS UPPER RIDGE ARE RESULTING IN GENERALLY FAIR WEATHER ACROSS MUCH OF THE CARIBBEAN SEA. HOWEVER...ACROSS THE W CARIBBEAN...DEEP MOISTURE IS BEING TRANSPORTED NORTHWARD TO THE W OF THE UPPER RIDGE AXIS...WHICH IS RESULTING IN ISOLATED SHOWERS S OF 20N W OF 81W. MODERATE TO STRONG EASTERLY TRADE WINDS ARE PRESENT ACROSS MUCH OF THE CARIBBEAN SEA. THESE TRADE WINDS ARE FORECAST TO CONTINUE THROUGH LATE TUESDAY AS THE 1028 MB SURFACE HIGH IN THE CENTRAL ATLC NEAR 34N46W MOVES EAST-NORTHEASTWARD. A COLD FRONT IS FORECAST TO ENTER THE NW CARIBBEAN SEA LATE TUESDAY AND REACH A LINE FROM CENTRAL CUBA TO HONDURAS ON WEDNESDAY BEFORE IT STALLS THROUGH FRIDAY. ATLANTIC OCEAN... SOUTHWESTERLY FLOW ALOFT CONTINUES TO INCREASE ACROSS THE W ATLC AS A DEEP TROUGH OVER THE E CONUS MOVES EASTWARD. A SURFACE COLD FRONT IN THE W ATLC ASSOCIATED WITH THIS DEEP TROUGH EXTENDS FROM SE OF SOUTH CAROLINA NEAR 32N80W TO THE N FLORIDA PENINSULA NEAR 30N82W. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS ALONG AND WITHIN 60 NM E OF THE COLD FRONT. TO THE E OF THIS FRONT...DEEP LAYER DRY AIR AND SUBSIDENCE ARE RESULTING IN GENERALLY FAIR WEATHER ACROSS MUCH OF THE SW AND CENTRAL ATLC. THIS SUBSIDENCE IS BEING ENHANCED AROUND THE 1028 MB SURFACE HIGH NEAR 34N46W. THE W ATLC COLD FRONT IS FORECAST TO MERGE WITH A REINFORCING SURFACE COLD FRONT ON TUESDAY. SW WINDS TO GALE FORCE ARE FORECAST FOR LOCATIONS N OF 29N WITHIN 360 NM E OF THE COLD FRONT FOR TUESDAY THROUGH EARLY WEDNESDAY. ALSO...AN UPPER TROUGH IS N OF 17N BETWEEN 25W-48W. THIS UPPER TROUGH IS ASSOCIATED WITH A SURFACE TROUGH THAT EXTENDS FROM 27N49W TO 29N44W TO 31N39W AND A SURFACE COLD FRONT THAT EXTENDS FROM 31N39W TO 32N35W TO NE OF THE DISCUSSION AREA. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF THE SURFACE COLD FRONT AND ISOLATED SHOWERS WITHIN 30 NM EITHER SIDE OF THE SURFACE TROUGH. ALSO...ATMOSPHERIC INSTABILITY AND UPPER LEVEL DIFFLUENCE ASSOCIATED WITH THE UPPER TROUGH ARE SUPPORTING SCATTERED SHOWERS FROM 26N-31N BETWEEN 17W-28W AND FROM 17N-22N BETWEEN 28W-37W. ACROSS THE TROPICAL ATLC...AN UPPER RIDGE IS PRESENT WITH AN AXIS EXTENDING FROM 5N8W TO 2N24W TO 1N31W. UPPER LEVEL DIVERGENCE NEAR THIS UPPER RIDGE IS ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ. $$ COHEN